Information transfer between Controllers in Angular (second method): $emit, $broadcast, $on

• • $emit can only pass events and data to the parent controller ($emit(name, args))
  • $broadcast can only pass events and data to the child controller ($broadcast(name, args))
  • $on is used to receive events and data ( $on(name, listener) )

  

  <div ng-controller="ParentCtrl">              <!--父级-->
    <div ng-controller="SelfCtrl">              <!--自己-->
      <a ng-click="click()">click me</a>
      <div ng-controller="ChildCtrl"></div>     <!--子级-->
    </div>
    <div ng-controller="BroCtrl"></div>         <!--平级-->
  </div>

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  JS：

  

  var app = angular.module('myApp', []);
  app.controller('SelfCtrl', function($scope) {
    $scope.click = function () {
      $scope.$broadcast('to-child', 'child');
      $scope.$emit('to-parent', 'parent');
    }
  });
   
  app.controller('ParentCtrl', function($scope) {
    $scope.$on('to-parent', function(event,data) {
      console.log('ParentCtrl', data);       //父级能得到值
    });
    $scope.$on('to-child', function(event,data) {
      console.log('ParentCtrl', data);       //子级得不到值
    });
  });
   
  app.controller('ChildCtrl', function($scope){
    $scope.$on('to-child', function(event,data) {
      console.log('ChildCtrl', data);      //子级能得到值
    });
    $scope.$on('to-parent', function(event,data) {
      console.log('ChildCtrl', data);      //父级得不到值
    });
  });
   
  app.controller('BroCtrl', function($scope){
    $scope.$on('to-parent', function(event,data) {
      console.log('BroCtrl', data);         //平级得不到值
    });
    $scope.$on('to-child', function(event,data) {
      console.log('BroCtrl', data);         //平级得不到值
    });
  });

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  Click click to run the result:

  ChildCtrl child controller.
  ParentCtrl parent

  The event event parameter in the $on method, the properties and methods of its object are as follows

  Event Properties	Purpose
  event.targetScope	The scope to emit or propagate the original event
  event.currentScope	The scope of the event currently being processed
  event.name	Event name
  event.stopPropagation()	A function that prevents further propagation (bubbling/capturing) of an event (this only applies to events emitted using `$emit`)
  event.preventDefault()	This method will not actually do anything, but will set `defaultPrevented` to true. The event listener does not check the value of defaultPrevented until its implementer takes action.
  event.defaultPrevented	True if `preventDefault` is called

  Tag: Angularjs

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